CALRETININ CONTAINING NEURONS AND EXCITOTOXIC INJURY

Calretinin(CR)是一种钙结合蛋白，存在于 脑神经元的亚群，如黑质(SN)和 大脑皮层。因为CR被认为与神经保护功能有关 SN，我们决定用L多巴处理中脑培养物， 神经递质多巴胺的前体，以及一种用于治疗 帕金森氏症。我们发现许多含TH的神经元 培养对L-多巴敏感，治疗后60%以上的菌株脱失。 当CR和TH共存于多巴胺能神经元时，这些神经元 对L多巴的有害作用具有免疫力。我们想要检查 这种中脑内含CR的神经元的这种保留是否 在其他胚胎原代神经元培养中发现。我们开发了一种新的 分离富含CR神经元的间脑区的解剖方法 并检查了间脑和皮质中含有CR的神经元 对兴奋性氨基酸的抵抗力。我们没有找到节制的证据 在两个亚群中都有。此外，当我们使用钙离子载体时 为了提高细胞内钙浓度，我们没有发现证据表明 含CR的皮质神经元的抵抗力。而CR一直以来 在中脑的备用神经元中被发现，我们得出结论 神经元中CR的存在不足以保护它 对抗兴奋性氨基酸毒性或钙超载。

Calretinin (CR) is a calcium binding protein that is found in subpopulations of brain neurons such as the substantia nigra (SN) and cortex. Because CR has been linked to neuroprotective functions in the SN, we decided to treat mesencephalic cultures with L-DOPA, the precursor to the neurotransmitter dopamine, and a drug used to treat Parkinson's disease. We found that many TH-containing neurons were very sensitive to L-DOPA in culture and over 60% were lost after treatment. When CR was colocalized with TH in dopaminergic neurons, these neurons were immune to the deleterious effects of L-DOPA. We wished to examine whether this sparing of CR-containing neurons in the mesencephalon was found in other embryonic primary neuronal cultures. We developed a new dissection procedure to isolate a diencephalic area rich in CR neurons and examined both diencephalic and cortical CR-containing neurons for resistance to excitatory amino acids. We found no evidence for sparing in either subpopulation. In addition, when we used a calcium ionophore to elevate cytosolic calcium concentrations, we found no evidence for resistance in CR-containing cortical neurons. While CR has consistently been found in spared neurons of the mesencephalon, we have concluded that the presence of CR in a neuron is not sufficient to protect it against either excitatory amino acid toxicity or calcium overload.